Fabrication of Biogenic Guanine Crystal/Ferromagnetic Film Hybrid Plate for Micro-Optical Micro-Electromechanical Systems

In micro-optical device and micro-electromechanical systems applications, the driving power and response time are the important factors for their performance. In this paper, a diamagnetic guanine crystal/ferromagnetic film hybrid plate is fabricated by the sputtering method in order to decrease the magnetic field amplitude required for the guanine crystal orientation. The behavior of the hybrid plate having a 5 nm-thick permalloy film in water under magnetic fields is investigated by using a three-axis Helmholtz coil. The hybrid plate rotates according to the horizontal magnetic field so that the length of (102) plane of guanine crystal is parallel to the field direction. For the vertical magnetic field, the hybrid plate easily stands up. These behaviors are attributed to the large shape anisotropy of ferromagnetic film of hybrid plate. Magnetic field amplitudes required for magnetic orientation drastically decrease compared to those for diamagnetic orientation of the pure guanine crystal. It has been demonstrated that LED lights which are simultaneously irradiated from different directions can be selectively introduced into the microscope by using the reflection of hybrid plate which is controlled with external magnetic fields.